Growing azaleas

While azaleas are nowhere near as popular as they were some years ago, they’re still hard to beat when it comes to producing a mass of garden colour in winter and spring. Azaleas vary in size from small, rather delicate shrubs that are happiest in pots, to the large, hardy indica varieties that seem able to survive all the climatic challenges that are thrown at them. The latter group includes salmon-pink ‘Splendens’, purple ‘Magnifica’ and white or bicoloured bloomers that can reach up to more than two metres tall.

General care

Most azaleas are at their happiest when grown in semi-shade or morning sun. These woodland plants have evolved to grow in the generations of leaf litter that have built up under forest trees. This type of leaf-mulch-derived soil is naturally acidic, which makes azaleas difficult to grow in soils that are tending towards the alkaline.

In order to achieve success with azaleas in alkaline soil areas, mix some moistened peat moss and milled cow manure into the planting area. Yates have an acidifying tonic called Yates Soil Acidifier Liquid Sulfur, that’s also worth applying on a semi-regular basis. Or grow your azaleas in pots where you’ll have more control over the conditions.

Always maintain a layer of organic mulch (e.g. a 10 centimetre thickness of old leaves) over the shallow roots. This insulates the roots and helps protect them from drying out. Feed a couple of times a year with a suitable slow release fertiliser.

Pruning

The Japanese have taken the art of pruning azaleas to new heights by clipping the plants into neat buns that rarely allow stray shoots to escape.

Pruning isn’t always necessary but it will help keep the plants in good shape. Prune immediately after flowering finishes. With some varieties (e.g. Red Wing – pictured) blooming continues for months so it’s important to be patient. After flowering, you can cut back as hard as you like because azaleas have the amazing ability to produce shoots from almost anywhere on the stem. Tall, wayward shoots can be shortened at other times of year but, remember, general cutting back close to flowering time will reduce the display.

Pests and diseases

Sadly, azaleas are affected by a number of pests and diseases. Fortunately, recent introductions have made their control much easier and more effective. Yates Baythroid protects from sap-sucking lace bugs. Azalea petal blight is an unpleasant fungal disease that spoils the flowers. It starts with water-soaked patches that gradually spread all over the blooms. The flowers then turn brown and hang on the plant. Yates new Zaleton fungicide will help stop the disease but spraying must start at bud stage.

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